The present inventors have developed an indolent dental cement containing a tannic acid derivative that is sparingly soluble in water, for which Japanese Patent Application No. 57-64630 was already filed. This dental cement shows a low solubility, and serves to alleviate the pain a great deal during cementation. Although a tannic acid-containing cement discolors, the aforesaid dental cement containing tannic acid derivative being sparingly soluble in water enjoys considerably limited discoloration.
However, it has been found that the aforesaid cement containing tannic acid derivative alone suffers more or less discoloration, inter alia, after the lapse of an extended period of time. The dental cement is designed for such that it starts being set at a point of time at which time it is applied in a patient's oral mouth after mixing. For that reason, it should preferably set in the mouth as soon as possible to give it a large crushing strength and a sufficient time for manipulation until the initial setting takes place. In view of such setting properties, it has also been noted that the aforesaid dental cement containing a tannic acid derivative alone is not necessarily ideal. Furthermore, it has been desired that the dental cement shows a further reduced solubility over an extended period of time in view of its durability.